[Listeriosis during pregnancy and excretion of listeria by laboratory workers (author's transl)].

The occurence of listeriosis during pregnancy in a medical technician and listeriosis in a neonate gave rise to an investigation of all laboratory workers being employed in this medical institute for the excretion of L.m. There had been no work with listeria or material containing listeria. In 11 out of 12 female employees, excretion of L.m. was observed over an extended period of time, also with a change of serotypes (see Table 1 or Fig. 1). It was supposed that frequent contact with laboratory rats could have caused the infection. However, L.m. could not be demonstrated in samples of faeces and in organs of these animals. The positive findings might be explained by the ubiquitous occurence of L.m. and the associated frequent oral intake. Of 37 strains of different serotypes isolated, the haemolysing serotypes 1/2a and one haemolysing strain of serotype 4a showed criteria of virulence, whereas the latter were missing completely in the non-haemolysing strains of the serotypes 4a and 4b (see table 4). Testing of the strains for sensitivity to chemotherapeutics showed a reduced sensitivity of serotype 4a, particulary to lincomycin, which might be used as a criterion differentiation. The good sensitivity of L.m. to trimethoprim must be emphasized (see Table 3).